Data Models into Database Designs - Technical MCQs

Q1:

Which constraint requires that the binary relationship indicate all combinations that must appear in the ternary relationship?

A MUST COVER

B MUST NOT

C Both of the above.

D None of the above is correct.

ANS:A - MUST COVER

Ternary and higher-order relationships can be treated as combinations of binary relationships.

There are three types of binary constraints: MUST, MUST NOT, and MUST COVER.

MUST NOT constraint: the binary relationship indicates combinations that are not allowed to occur in the ternary relationship.

MUST COVER constraint: the binary relationship indicates all combinations that must appear in the ternary relationship.